FR2782550A1 - MOTOR VEHICLE HEADLIGHT EQUIPPED WITH MEANS TO SELECTIVELY EMIT A BEAM FOR RIGHT OR LEFT TRAFFIC - Google Patents

Abstract

A motor vehicle headlamp includes a reflector (20) and a lamp. The reflector selectively generates two types of passing beams, respectively for left-hand traffic and for right-hand traffic, by cooperating with the lamp occupying two angular positions. The reflector carries a turntable (30) on which the lamp is fixed. Driving means (32, 34, 35) are provided for manually rotating the plate to one or the other from two operating positions corresponding to the angular positions of the lamp, and wedging means between the assembly formed by the plate and the lamp on the one hand and a fixed part of the projector on the other hand, to ensure the stability of the positioning of the plate in each of its positions.

Description

The present invention relates generally to floodlights

  motor vehicles, and in particular relates to a new dipped beam headlamp which can be adapted in an extremely simple manner for a right-hand traffic direction or for a left-hand traffic direction. We have already tried, in projectors of the elliptical type where the cut-off of a passing beam is defined by a mask or screen placed on the light path between a generally elliptical mirror and a converging lens, to be able to selectively modify the shape of the mask to respectively generate a beam for traffic on the right and a beam for traffic

to the left.

  These lessons cannot however be transposed to the case of a projector of the type in which the beam is formed directly by the mirror cooperating with a source (possibly partially obscured), to a mirror and if necessary by deflecting elements such as striations. or prisms formed on the closing glass. Indeed, in this type of projector (an example of which is a projector using a standard type lamp "H4" in a parabolic reflector), the shape of the mirror and / or the arrangement of the deflecting elements is decisive in giving a good quality cut-off beam for a defined direction of traffic. In this respect, the use of a "vacationer's mask" formed of an opaque adhesive strip placed in an appropriate place on the lens of the headlight when the vehicle has to change direction of traffic is a palliative with which the modified beam is hardly satisfying by

terms of visual comfort.

  Thus, headlamps for left-hand traffic and right-hand traffic must generally have reflective surfaces and / or

  ice creams different from each other.

  In addition, the Applicant has developed in recent years mirrors whose reflecting surfaces are capable of generating by themselves beams for traffic on the right or for traffic on the left having the required photometry, in particular in terms

  cut, homogeneity and width.

  But here again, the reflecting surface is designed specifically for a given direction of circulation, and the same surface cannot be suitable for both directions.

traffic.

  Furthermore, there is now a tendency to equip the projectors with discharge lamps, known for their light intensity substantially greater than that of a

  filament, for lower power consumption.

  The high intensity of this type of source, as well as the presence in the vicinity of the light arc itself of secondary light sources linked to the accumulation of salts in certain regions of the lamp, or to reflections on the electrodes , however, pose special problems, partly solved by a very specific design of the surface

reflecting from the mirror.

  Thus the specificity of reflective surfaces for left-hand traffic and for right-hand traffic

  is often even more marked with this type of lamp.

  A consequence of this specificity is the need to use different mold punches for the two types of traffic, and if necessary different mold pockets also, which of course contributes to a high tool cost. In order to overcome these limitations of the state of the art, it could be interesting to design a projector in which not only the same reflecting surface, but also the same type of lamp, can be used to achieve indifferently, by a simple movement of the lamp, a dipped headlamp for left-hand traffic and a headlamp

  cross for right-hand traffic.

  Thus the present invention aims to propose a headlamp which first of all has a reflecting surface suitable for generating, depending on the position of the lamp, a passing beam for traffic on the left or a passing beam for traffic on the right, and which addition has particularly simple, economical and reliable means to ensure proper positioning of the lamp in its

  orientation corresponding to the desired traffic direction.

  To this end, the invention provides a motor vehicle headlamp comprising a reflector and a lamp mounted in said reflector, characterized in that the reflector has a reflecting surface capable of selectively generating two types of passing beams, respectively for left-hand traffic and for right-hand traffic, by cooperating with a lamp correspondingly occupying one of two given angular positions, in that the reflector carries a plate which can rotate relative to said reflector and on which said lamp is fixedly mounted, and in this that there are provided drive means for manually rotating the plate to one or the other from two operating positions, each operating position corresponding to a given angular position of the lamp, and means for wedging between the assembly formed by the plate and the lamp on the one hand and a fixed part of the projector on the other hand, for ensure the stability of the positioning of the plate in each

of its operating positions.

  Preferred, but non-limiting aspects of the headlight according to the invention are the following: - the plate has a generally circular shape and is guided in rotation by arrangements

  provided at the rear of the reflector.

  - The projector has a unique locking means to firstly ensure the fixed mounting of the lamp on the plate and secondly to ensure the retention

  axial of the plate relative to the reflector.

  - Said locking means is constituted by an elastic pin bearing against smooth areas of a

lamp flange.

  the drive means of the plate comprise a rod mounted in an articulated manner on the

platinum.

  - the drive means further include a

  articulated lever on the rod and able to move it

  this. - The drive means further comprise a screw nut assembly of which one of the elements is integral

in translation of the rod.

  - one of the elements of the screw-nut assembly is

  formed on a projector housing.

  the wedging means comprise at least one finger integral with the reflector and urged elastically in the direction of a notch in the lamp. - each finger has a rounded end, and the notch has a width less than that of

each finger.

  the wedging means consist of the screw-nut assembly, the end positions of which are determined so as to correspond to the two

  deck operating positions.

  - cooperation between threads of the whole screw-

  nut has substantially zero axial play and a

  predetermined minimum coefficient of friction.

  - the lamp is a discharge lamp equipped with

means of concealment.

  - the lamp is a lamp comprising at least one incandescent filament fitted with a cup

occultation.

  Other aspects, aims and advantages of the invention

  will appear better on reading the description

  following of two embodiments of the invention, made with reference to the accompanying drawings, in which: FIG. 1a is a schematic rear view of a set of mirror and lamp in a first mutual position, making it possible to obtain a passing beam for traffic on the right, FIG. 1b is a schematic back view of the same mirror and the same lamp, in a second mutual position making it possible to obtain a passing beam for traffic on the left, FIGS. 2a and 2b illustrate by isocandela curves the shape of the crossing beams generated respectively by the mirror / lamp assembly of FIG. 1a and that of FIG. 1b, without intervention of the closing glass, FIG. 3 is a more detailed back view of a preferred embodiment of the mirror of Figures la and lb, Figure 4 is a partial rear view on an enlarged scale of the mirror / lamp assembly of Figures la and lb, Figure 5 is an elevational view side view of a concealer equipping the mirror / lamp assembly of FIGS. 1a, 1b and 4, FIGS. 6a and 6b are rear views of a first embodiment of means making it possible to selectively bring the lamp into the two operating positions of the projector according to the invention, in order to obtain a beam by circulation to the right and to the left, respectively, FIGS. 7a and 7b are two detailed views of the means making it possible to ensure the stability of the positioning of the lamp in each of the two operating positions corresponding respectively to Figures 6a and 6b, and Figures 8a and 8b are rear views of a

  second embodiment of the aforementioned means.

  Referring firstly to Figures la, lb, 3 and 4, there is shown a lamp / mirror assembly of a dipped headlight which comprises a lamp

discharge 10 and a mirror 20.

  The lamp 10 comprises, conventionally, a first generally cylindrical bulb 11, having at the arc S a boss, surrounded by a second cylindrical bulb 12 on which are formed two opaque longitudinal strips, respectively 13 and 14, intended for mask certain areas of the mirror with respect to the source to prevent said mirror, having recesses between surfaces in these areas, from being able to emit parasitic radiation above the desired cut-off. There is also provided in association with the lamp a cover or direct light concealer 15, which comprises a front concealment part 16 fixed to the region of the bottom of the mirror (preferably directly to the support of the lamp) using two opaque longitudinal tabs 17 and 18, whose width and position relative to the lamp are judiciously determined so that these tabs also form blackout bands cooperating, as will be described below, with blackout bands

13 and 14 of the second bulb 12.

  The mirror 20 in this case comprises four zones, namely a lower zone 21, an upper zone 22 and

two lateral zones 23 and 24.

  These areas are separated by transition planes, P13, P14 and P23, P24 respectively, passing in the vicinity, or preferably by the optical axis of the

mirror.

  The lower zone 21 is capable of generating, from the source, a portion of the beam that is strongly spread in width, of good homogeneity and delimited in the upper part by a cut generally

horizontal.

  For this purpose, this zone is preferably constructed from individual streaks S21 capable on the one hand of spreading the light laterally, and on the other hand of folding down all the images of the source in such a way that their highest regions are

  essentially aligned with the above cut.

  These streaks are for example formed from self-generating beam surfaces with horizontal cutoff, as described in particular in document FR-A-2 536 503, the horizontal generators of which are parabolic or not, are chosen to be different from each other. so as to intersect, in particular along the curved lines as illustrated, with a slight bend, said horizontal generatrices being moreover chosen to give the beam the horizontal distribution

required.

  It will be observed here that the surface 21 is constructed not as a function of the position of the main source S constituted by the arc of the lamp (see FIG. 4), but advantageously as a function of the position of the secondary light source S 'constituted by the accumulation of salts in bulb 11 of the lamp, essentially below the arc (see also in

figure 4).

  The upper zone 22 of the mirror is preferably constructed in the same way as the lower zone 21, with grooves S22 capable of spreading the light below a horizontal cut, with a

good homogeneity.

  However, with regard to zone 22, it is as a function of the position of the main source that constitutes the arc of the lamp that these different streaks

S22 are built.

  The zones 23 and 24 extend on either side of the lamp, and are designed so as to be able, according to the angular position of the lamp and therefore of its blackout bands relative to the mirror, to complete the beam as generated by the lower and upper zones 21 and 22 to selectively carry out a cutoff bearing on the left (traffic on the left) or on the right (traffic on the right). These zones 23 and 24 are produced symmetrically with respect to the axial vertical plane of the mirror, and only the

  zone 23 will be described in detail.

  Zone 23 is divided into two sub-zones, 231 and 232 respectively, the first adjacent to the lamp and the second extending between the first and the

side edge of the mirror.

  The sub-area 231 is advantageously constituted by a reflecting surface in accordance with document FR-A-2 609 146 in the name of the Applicant, which has the property of behaving, in cooperation with a concealer limiting the angular field of radiation of the source (of the type of the front filament of a standardized lamp "H4"), like a paraboloid of revolution, while ensuring a spreading of the light under the cut, whether

horizontal or inclined.

  For more details on such a surface, refer to the aforementioned document. A surface is preferably chosen which ensures convergence of the radiation, this convergence being however adjusted so that the screen 15 of the lamp does not intercept a

excessive amount of light.

  Sub-area 232, for its part, consists of a base surface in the form of a paraboloid of revolution, onto which light spreading streaks have been projected, along the cut, such projected streaks being described in particular in the

  document FR-A-2 710 393 in the name of the Applicant.

  Preferably, these streaks comprise upper streaks S232h, extending vertically above the axial horizontal plane of the mirror, and lower streaks S232b, extending below said axial horizontal plane and having an inclination y preferably equal to about 15 from the vertical. In this way, the upper streaks S232h are able to spread the light horizontally, while the streaks S232b are able to spread the light in a

  inclination of about 15 with respect to the horizontal.

  It will be observed here that the configuration of the sub-area 231 and of the streaks of the sub-area 232 is such that these surfaces provide a significantly less lateral spread of the light than the areas 21 and 22.

described above.

  As we said, zone 24 is made symmetrically from zone 23, with two sub-zones 241 and

242 and streaks S242h and S242b.

  Advantageously, the half-planes of separation between the zones are inclined as follows: for the half-planes P13 and P14: at 28 below the horizontal, symmetrically (angle P in FIG. 4); for the half planes P23 and P24: at 25 above the horizontal, also symmetrically (angle a on the

figure 4).

  Now with reference to FIG. 4 in particular, the arrangement of the

  lamp 10 and its various blackout strips.

  Conventionally in itself, the lamp has on its outer bulb 12 two opaque longitudinal strips 13 and 14. In the illustrated position, corresponding to a beam for traffic on the left, the strip 13 located on the left has its upper edge contained in the plane vertical passing through the base of the light arc, while the strip 14 has its upper edge contained in a plane passing through said base of the arc and tilted 15 downwards. These two upper edges play a role similar to that of the two opposite edges of a cup

  of occultation of a standard filament lamp "H4".

  From their upper edge, the two bands 13 and 14 extend downward over an angular interval of approximately 25 around the axis of the bulb 12, and are thus arranged symmetrically with respect to an inclined plane of symmetry PS 7.5 with respect to the axial vertical plane. The two blackout bands 17 and 18 have an angular extent which is positioned relative to that of the bands 13 and 14 as follows: still in the position of Figure 4, the blackout bands 17 and 18 each have an edge upper located so that they do not obscure any radius from the arc and passing over the upper edge of the associated strip 13, 14, so as to let the arc and these upper edges define the desired half cuts. Furthermore, the blackout strip 17 has a lower edge such that no ray from the lamp, and in particular from the region of the salts S ′, cannot

  meet the lateral zone 23 of the mirror.

  The upper edge of the strips 17 and 18 and the lower edge of the strip 17 being thus defined, the strips 17 and 18 are dimensioned so as to be

  symmetrical with respect to the plane of symmetry PS.

  In this way, when the lamp 10 occupies an angularly offset position of 15 to generate a beam suitable for traffic on the right, the lower edge of the strip 18 will play the same occultation role as in

  in the previous case, the lower edge of the strip 17.

  As mentioned above on several occasions, it is understood that the lamp 10 provided with its shield 15 can be mounted in the mirror 20 so as to be able to adopt one of two stable orientations, one being illustrated on figure la and the other being

illustrated in Figures 1b and 4.

  We will now describe the means which make it possible to vary the position of the lamp / blackout assembly between two angular positions corresponding to the two emission modes of the projector according to the invention, and to ensure the stability of the assembly of each. of these

two positions.

  FIGS. 6a and 6b are two representations of a first embodiment of these means, in two positions making it possible to emit respectively a beam for right-hand traffic and a beam for left-hand traffic. These figures also show the contour of the reflector 20 at the bottom of which the

  means mentioned above are implemented.

  With reference to FIG. 6a, a plate 30 of generally circular shape is pivotally mounted around the optical axis of the projector, concentrically with a lamp hole which makes it possible to engage the lamp 10 and the shield 15 in said reflector, not shown in this figure, which are intended to be fixedly mounted on the plate in a reference position in the axial and transverse directions as well as angularly. The dashed line 31 illustrates the contours of the

lamp access hatch.

  A tab 32 is integral with the plate 30 and projects radially outward from the perimeter of the plate, extending substantially horizontally in

  the configuration shown in Figure 6a.

  The lower end of a vertical rod 34 is articulated on an axis 320 formed in the free end region of the tab 32. The upper end of the rod 34 is articulated on a midpoint of a control arm 35 one end of which (on the left in the figures) is articulated on an axis 351 secured to the reflector 20, and the other end of which forms an actuation region accessible to the user's finger to

  through the lamp access hatch.

  The movements of the plate 30 and its lug 32, the rods 34 and the arm 35 are each effected substantially in a plane transverse to the optical axis of the reflector. Around the pivoting plate 30 is provided concentrically a crown 36 consisting for example of a rear flange molded on the

reflector.

  A pin 37 in spring-wire, of conventional type, is articulated on the rear of the reflector 20 and can be locked to retain in a axial direction on the one hand the lamp 10 on the plate 30, and on the other hand the plate on a bearing surface formed on the rear of the reflector and delimited by the crown 36. This fixing, which blocks the lamp against any rotation relative to the plate (by conventional angular indexing means), does not however prevent the rotation movement of the plate around the optical axis of the reflector, rotation movement which is moreover guided by the crown 36. This freedom of rotation of the plate is for example ensured by pressing the bent areas of range of the pin against smooth areas of the lamp bezel. This pin ensures easy disassembly of the lamp by

view of its replacement.

  As best seen in FIG. 7a, a flange of the lamp comprises in a well-defined angular position a substantially hemispherical notch 300 of given diameter, opening on its periphery

exterior facing the crown 36.

  The crown 36 has two respective blind holes 361 and 362 spaced at a predetermined angle, in this case 15, and opening

  radially inward on the lamp.

  Two movable fingers 3610 and 3620 housed in the respective blind holes 361 and 362 are biased radially against the periphery of the lamp by respective springs 3611 and 3621 compressed between the bottom of the respective blind holes 361 and 362 and an inner bearing face of the associated finger. These fingers have substantially hemispherical free ends, and a diameter slightly larger than

that of notch 300.

  When the notch 300 of the lamp is opposite one of the two fingers, the spring associated with the latter thus partially engages the rounded end

said finger in the notch.

  This cooperation of the finger and the notch 300 of the lamp thus makes it possible to ensure the stability of the lamp and of the plate of which it is integral in a

given angular position.

  On the other hand, the fact that the pins cannot fully engage in the notch 300 allows, by a reasonable effort, to easily release the lamp and the

  platinum by action on the linkage described above.

  The stiffness of the springs 3611 and 3621 is in this respect chosen to be large enough to reliably maintain the plate in its position, in particular despite vibrations specific to the operation of the vehicle, in the absence of any stress coming from the linkage, but in at the same time weak enough to

  allow an easy change of position of the plate.

  The two fingers 3610 and 3620 spaced 15 on the periphery of the crown define the two operating positions of the lamp 10, so that the headlight selectively emits a passing beam for left-hand traffic or a passing beam for

  right hand traffic, respectively.

  Alternatively, one could naturally provide

  single finger able to cooperate with two notches.

  The lamp is moved to one or the other of these two reference positions by operating the arm 35 with the finger through the lamp access door. In particular, by lifting the free end of the arm 35 from the position illustrated in FIG. 6a, said arm drives up the rod 34 and the tab 32, which causes the rotation of the plate 30 and therefore of the lamp, to the other stable position. Thus Figures 6b and 7b are views similar to those of Figures 6a and 7a, showing the plate in its second position, corresponding to a direction of

left hand traffic.

  Conversely, by pushing the arm 35 down, the plate is returned to its position illustrated on the

Figures 6a and 7a.

  Referring now to Figures 8a and 8b, there is shown a second embodiment of the invention in which the plate 30 and its tab 32 are substantially identical to those of Figures 6a and 6b, but in which the means of movement and plate timing are different. In FIGS. 8a and 8b, elements or parts identical or similar to those of FIGS. 6a and 6b have been designated by the same

reference signs.

  In this second embodiment, the movement of the tab 32 is ensured by a rod 41 articulated on the tab 32 at its lower end and secured in axial movement, at its upper end, with a screw 40 on which it is mounted free in rotation and linked in translation by any cooperation of forms of a type known per se such as a ball joint

(not shown).

  The screw 40 cooperates with a nut 42 formed for example in the upper wall of the projector housing (not shown) and has a portion of

  maneuver 401 located outside said housing.

  The manual rotation of the screw by its operating part 401 makes it possible to selectively bring the plate 30 into one or the other from two reference positions, which are here preferably determined by the end of travel of the screwing of the screw 40 in its nut 42,

  resulting from an appropriate design of these elements.

  The stability of the plate 30 and of the lamp 10 in each of the reference positions is also ensured by an appropriate design of the screw and the nut, minimizing the axial clearances at the level of the threads and at the same time ensuring a coefficient sufficient friction to avoid, in particular by the effect of vibrations due to the operation of the vehicle, any

  Unwanted relative rotation between the screw and the nut.

  An advantage of this second embodiment is that the lamp position can be changed directly from outside the projector housing, without having to open the lamp access door. In this regard, the first embodiment can be easily adapted so that the operation is done, there too, from outside the housing. As indicated above, the present invention applies to a discharge lamp projector

in particular of the type described.

  It can also be applied to a headlamp equipped with a lamp having a filament cooperating with a concealment cup, such as a lamp of standard type "H4", cooperating either with a parabolic reflector, or with a reflector having surfaces specifically designed to generate the passing beams for left-hand traffic and for right-hand traffic depending on the position of the cup.

Claims (14)

  1. Motor vehicle headlamp comprising a reflector (20) and a lamp (10) mounted in said reflector, characterized in that the reflector has a reflecting surface capable of selectively generating two types of passing beams, respectively for left-hand traffic and for right-hand traffic, by cooperating with a lamp correspondingly occupying one of two given angular positions, in that the reflector carries a plate (30) which can rotate relative to said reflector and on which said lamp is fixedly mounted, and in that there are provided drive means (32, 34, 35; 32 40, 41, 42) for manually rotating the plate to one or the other from two operating positions, each position operating mode corresponding to a given angular position of the lamp, and of the wedging means (3610, 3620, 300; 40, 42) between the assembly formed by the plate and the lamp on the one hand and a fi on the other hand, to ensure the stability of the positioning of the plate in each of its operating positions.   2. Projector according to claim 1, characterized in that the plate (30) has a generally circular shape and is guided in rotation by   arrangements (36) provided at the rear of the reflector.   3. Projector according to claim 2, characterized in that it comprises a single locking means (37) for on the one hand ensuring the fixed mounting of the lamp (10) on the plate (36) and on the other hand ensuring the axial retention of the plate relative to the reflector (20). 4. Projector according to claim 3, characterized in that said locking means is constituted by an elastic pin (37) bearing against   smooth areas of a lamp flange (10).   5. Projector according to one of claims 1 to   4, characterized in that the drive means of the plate comprise a rod (34; 41) mounted so articulated on the plate.   6. Projector according to claim 5, characterized in that the drive means further comprise a lever (35) articulated on the   rod and able to move it.   7. Projector according to claim 5, characterized in that the drive means further comprise a screw-nut assembly (40, 42) one of which (40) of the elements is integral in translation with the rod (41).   8. Projector according to claim 7, characterized in that one (42) of the elements of the screw-nut assembly is formed on a housing of the projector.   9. Projector according to one of claims 1 to   6, characterized in that the wedging means comprise at least one finger (3610, 3620) integral with the reflector (20) and resiliently biased towards a notch (300) of the lamp.   10. Projector according to claim 9, characterized in that each finger (3610, 3620) has a rounded end and in that the notch (300)   has a width less than that of each finger.   11. Projector according to one of claims 7   and 8, characterized in that the wedging means are constituted by the screw-nut assembly (40, 42), the end positions of which are determined so as to correspond to the two operating positions of the platinum (30).   12. Projector according to claim 11, characterized in that the cooperation between threads of the screw-nut assembly (40, 42) has a substantially zero axial play and a predetermined minimum coefficient of friction.   13. Projector according to one of claims 1 to   12, characterized in that the lamp (10) is a lamp with   landfill equipped with concealment means.   14. Projector according to one of claims 1 to   12, characterized in that the lamp is a lamp comprising at least one incandescent filament equipped with a blackout cup.